Foam stabilizing composition



Patented July 20, 1943 I FOAM STABILIZING COMPOSITION Arthur FerdinandRatzer, Hanworth, England,

assignor to Pyrene Minimax Corporation, Newark, N. 3., a corporation ofDelaware .No Drawing. Application May 26, 1939, Serial No. 275,802. InGreat Britain May 31, 1938 Claims (01. 252-307) This invention relatesto foam stabilizing substances capable of forming stable foams withwater and a gas, the method of preparing such substances, and the methodof forming fire extinguishing foam with such substances.

Numerous proteinaceous materials including degradation products ofproteins have been used or suggested for the production of foam forvarious purposes. For example, in the fire extinguishing art, glues andcasein products have been recommended and used. These materials,however, do not fully satisfy the present requirements of a foamstabilizing agent which requirements ar becoming more and more exactingfor the manufacture of fire extinguishing foam, particularly the makingof air foam utilizing a stream of water to aspirate air in the foamproduction.

An object of this invention is to provide a foam stabilizing materialwhich is readily soluble in water and produces a. high yield of verystable foam.

Another object is the adaptation of a product resulting from acontrolled hydrolysis of proteins as a foam stabilizing material in theproduction of fire extinguishing foam.

Further objects and advantages of this invention will be apparent andwill be explained in connection with the following description.

It has been discovered that foam stabilizing substances can be producedhaving foam pro-- ducing properties of a surprisingly high order andyielding foams of high stability by subjecting animal or other proteinto a controlled hydrolysis. Particularly suitable proteinaceousmaterials for this purpose are proteins consisting principally ofkeratins, albumens, globulins or hemoglobins (which are sometimesregarded as globulins) or more than one of these. One or other of theseproteins is found in substantial quantities in horns, hoofs, hair,feathers, blood, soya bean meal, pea flour and maize meal, and thesenatural materials are suitable for producing the foam stabilizingmaterials of this invention. The controlled hydrolysis of the protein ispreferably carried to a point such that at least 25% of the nitrogenpresent in the water-soluble products of the hydrolysis is present inthe form of peptones. As the hydrolysis proceeds, the proportion ofnitrogen in the form of peptones increases until a maximum is reached,and if the hydrolysis is continued further, the peptones then break downto form lower amino acids and the proportion of nitrogen in the form ofpeptones decreases. The hydrolysis or degradation is preferably carriedout to produce as high a proportion of nitrogen in the form of peptonesas possible and such a proportion is preferably carried at least as highas 50%, although inpractice it is difficult, if not impossible, for theproportion of the nitrogen in the form of peptones to exceed By thenitrogen present in the form of peptones is meant that amount of thetotal nitrogen present that can be determined as follows: An aqueousdilute solution of the products is saturated with magnesium sulphate inthe presence of 0.3% of sulphuric acid calculated on the total weight ofthe saturated solution, and the precipitate is removed. The nitrogen inthe remaining solution that does not react as amino acids in Sorensonsformaldehyde titration method of determining amino acids is regarded asthe nitrogen present in the watersoluble products in the form ofpeptones, and its percentage can be calculated after determining thetotal nitrogen in the water-soluble products.

Very goodresults are obtained when there is employed as hydrolysingagent an oxide of an alkaline earth metal or magnesium oxide. Thehydrolysing agent preferably employed is calcium oxide, i. e., lime, butbarium oxide and strontium oxide are also suitable. Magnesium oxide canbe used, but the results are not quite so good, probably on account ofits low solubility. Of course, in the reaction the oxides willinvariably form the hydroxides, and it is probably in .this form thatthey will react with the protein.

Indeed, the oxides can be introduced as hydroxides. Hence it is to beunderstood that where in the claims a reference is made to the oxides,-the hydroxides are included also.

It hasv been found that if the hydrolysis or degradation of the proteinsis controlled and not allowed to proceed too far, the point is reachedat which a neutral 1% aqueous solution" of the water-soluble hydrolysisproducts yields in apparatus for producing fire-extinguishing air foam afoam having a volume at least six times that of the solution.

If desired, there may be added to such hydrolysis products a furtherfoam stabilizing substance for the purpose of increasing the stabilityor lasting power of the foam produced. Thus there may be incorporated inan aqueous solution of the water-soluble products of the hydrolysis asalt which on dilution of the solution or on formation of the foam ishydrolyzed to an insoluble hydroxide. Among such substances are ferrousand ferric salts (in either case ferric hydroxide is the insolublehydroxide) and ferrous sulphate is especially suitable.- It should beadded that if a strongly acid salt is used the acidity of the solutionmay need to be modified in order to avoid precipitation of nitrogenoussubstances when the salt is added. The addition of such furtherstabilizing materials is not necessary, however, since the hydrolysisproducts themselves are capable of producing a foam with a highstability. i

The protein to be hydrolyzed may conveniently be horn or hoof meal,dried blood or mixtures of these materials. Other starting materials arepea flour, maize flour and soya bean meal (1. e., the material left whenthe oil has been extracted from soya beans). If pea flour or maize mealis used, the starch should first be extracted, as otherwise it wouldinterfere with the hydrolysis.

The hydrolysis can be carried out by heating the proteinous materialwith the oxide and water at atmospheric or other pressure, and it is ofadvantage to introduce a salt in addition to the hydrolyzing agent.Especially when lime is being used a soluble calcium salt, for instancecalcium chloride, is preferable, and when lime is used it is sufllcientto add a little hydrochloric acid, which is neutralized with formationof the chloride. However, sodium chloride and other salts are alsosuitable. If lime is employed as a hydrolyzing agent in conjunction withcalcium chloride, the proteinaceous material, lime and calcium chlorideare preferably boiled with'water at atmospheric pressure for a suihclenttime to produce the desired degree of hydrolysis.

A particularly convenient method of continuing the process is toneutralize the boiled product with an acid such as 20% sulfuric acid,boil the neutralized product carefully to expel undesirable gases, add acalculated'quantity of sodium sulfate to convert the calcium present insolution to calcium sulfate. leaving a sodium salt, and then filter andwash the residue. The filtrate and washings are then combined andconcentrated by evaporation until a liquid containing about 50% byweight of solids is obtained. The liquid is a stable foam stabilizingmaterial and particularly useful for the production of air foam for fireextinguishing purposes. If desired, the evaporation may be continued tocomplete dryness and the resulting solid substance used as the foamstabilizing material.

For a more complete understanding of the invention, the followingexamples of preparing protein hydrolysis products are given:

Example 1.-100 lbs. of horn and hoof meal, 20 lbs. of slaked lime and 6lbs. of calcium chloride are boiled with about 300 lbs. of water atatmospheric pressure for a period of about four hours with continuousagitation. The product is then neutralized with 20% sulfuric acid,boiled for a period of about 30 minutes to expel undesirable gases, andfurther treated and concentrated as described earlier in thisspecification.

If desired a somewhat larger or smaller quantity of slaked lime may beemployed, but in practice the amount of slaked lime should not be lessthan 10 lbs, when the other quantities are as indicated above. If lessthan 20 lbs. is employed it is advisable to increase the time ofheating, heat at an increased temperature under pressure (for instancein an autoclave) or both. The quantity of calcium chloride may vary, butin practice not less than three lbs. should be employed.

In this example, instead of boiling the mixture for four hours it may beheated for 8 hours at C. with continuous agitation.

Example II.Dried blood or soya bean meal is treated in a similar mannerto the horn and hoof meal of Example 1, the quantities of reagents beingthe same.

The foregoing conditions are quite generally applicable to thepreparation of protein hydrolysis products from various proteinaceousmaterials. However, in order to obtain the exact degree of hydrolysisdefined, the conditions must be rigidly controlled. With differentsamples of horn and hoof meal, dried blood or soya bean meal, there maybe'somevariation in composition and in'such cases it will be necessaryto alter slightly the conditions given in the foregoing examples. 4

The protein hydrolysis products are particularly usefulfor producing airfoam for fire extinguishing purposes, and for this purpose may be addedin a proportioned amount to a stream of water. The stream of watercarrying the foam stabilizing material will'then be divided into one ormore jets for aspirating air and producing the foam, as is wellunderstood in the art. The hydrolysis products may also be added to thewater simultaneously with or just subsequent to the incorporation of theair therein.

The terms and expressions which I have employed are used as terms ofdescription and not of limitation, and I have no intention, in the useof such terms and expressions, of excluding any equivalents of thefeatures shown and described.

Subject matter disclosed but not claimed herein is claimed in my.divisional application Ser. No. 479,603, filed March 18, 1948.

I claim: 1

1. A foam stabilizing composition comprising an aqueous solution ofhydrolysis products obtained by hydrolyzing a protein selected from theclass consisting principally of k'eratins, albumens, globulins,hemoglobins and seed meal proteins by means of an alkaline compoundselected from the class consisting of oxides and hydroxides of thealkaline earth metals and masnesium, said products containing at least25% of their nitrogen content in the form of peptones.

2. A foam stabilizing composition prepared for making fire extinguishingair foam comprising an aqueous solution of hydrolysis products obtainedby hydrolyzing a protein selected from the class consisting of keratins,albumens, globulins, hemoglobins and seed meal proteins by means of analkaline compound selected from the class consisting of oxides andhydroxides of the alkaline earth metals and magnesium, said productscontaining at least 50% of their nitrogen content in the form ofpeptones.

3. A foam stabilizing composition comprising an aqueous solution ofhydrolysis products obtained by hydrolyzing a solution of blood by meansof an alkaline compound selected from the class consisting of oxides andhydroxides of alkaline earth metals and magnesium, said productscontaining at least 25% of their nitrogen content in the form ofpeptones.

4. A foam stabilizing composition comprising an aqueous solution ofhydrolysis products obtained by hydrolyzing a solution of hoof meal bymeans of an alkaline compound selected from the class consisting ofoxides and hydroxides of alkaline earth metals and magnesium, saidproducts containing at least 25% of their nitrogen content in the formof peptones. V

5. A foam stabilizing composition comprising an aqueous solution ofhydrolysis products obtained by hydrolyzing a solution of horn meal bymeans of an alkaline compound selected from the class consisting ofoxides and hydroxides of alkaline earth metals and magnesium, saidproducts containing at least 25% of their nitrogen content in the formof peptones.

6. A method of preparing a foam stabilizing solution comprising heatinga protein selected from the class consisting principally of keratins,albumens, globulins, hemoglobins and seed meal proteins in an aqueousmedium with an alkaline compound selected from the class consisting ofoxides and hydroxides of alkaline earth metals and magnesium tohydrolyzethe protein, and arresting the hydrolysis when the products ofthe hydrolysis have at least 25% of their nitrogen content converted topeptones.

7. A method of preparing a foam stabilizing solution comprising heatinga solution of blood with an alkaline compound selected from the classconsisting of oxides and hydroxides of alkaline earth metals andmagnesium to hydrolyze the protein, and arresting the hydrolysis whenthe products of the hydrolysis have at least 25% of their nitrogencontent converted to peptones.

A method of r paring a foam stabilizing solution comprising heating asolution of hoof lyze the protein, and arresting the hydrolysis when theproducts of 25% tones.

10. A method of preparing a foam stabilizing solution comprising heatinga protein selected from the class consisting principally of keratins,albumens, globulins, hemoglobins and seed meal proteins in an aqueousmedium with an alkaline compound selected from the class consisting ofthe hydrolysis have at least oxides and hydroxides of alkaline earthmetals and magnesium to hydrolyze the protein, and arresting thehydrolysis when the products of the hydrolysis have at least about 50%of their nitrogen content. converted to peptones.

ARTHUR FERDINAND RATZER.

of their nitrogen content converted to pepl of their nitrogen contentconverted to pep-

